machovec



Feb. 9, 1960 F. J. MACHOVEC 7 MULTIPLE-STATION BLADE SHARPENER Filed Oct. 7, 1957 2 Sheets-Sheet 1 Feb. 9, 1960 F. J. MACHOVEC 2,924,047

' MULTIPLE-STATION BLADE S-IARPENER Filed Oct. 7, 1957 2 Sheets-Sheet 2 F850 J. MCA OI EC INVENTOR.

United States Patent 1 MULTIPLE-STATION BLADE SHARPENER Fred J. Machovec, Pasadena, Calif.

Application October 7, 1957, Serial No. 688,616 8 Claims. (Cl. 51-102) This invention relates to power driven blade shapeners and more particularly to an improved unitary device featuring a plurality of blade sharpening stations adapted to be used singly or simultaneously and wherein one of such stations is especially equipped for the sharpening of scissor type blades.

Many proposals have been made heretofore for blade sharpeners utilizing power driven abrasive wheels and featuring various devices for supporting the blade while being sharpened. However, prior devices are lacking in versatility and in the efficiency with which they can be used to sharpen blades of widely varying sizes, shapes and characters. Furthermore, prior wheels are not adapted for use in sharpening more than one blade from separate operating stations. A further shortcoming of prior devices is their lack of portability and adaptability to grind both scissor type and knife blades.

The present invention seeks to obviate the foregoing and other disadvantages of prior design by providing an unusually simple self-contained unit adapted to be carried readily from place to place and featuring a single power driven abrasive wheel in combination with two independent grinding stations adapted to be used simultaneously by different operators without interference with one another. To this end the present unit includes a motor driven abrasive wheel ofiset to one side of a base plate leaving a smooth flat surface along one edge of the base plate for slidably supporting a bodily movable scissor-blade holder. Disposed on the opposite side of the base are a pair of blade supporting facilities having separately adjustable means for supporting a knife blade against the opposite faces of the wheel while being pulled radially thereacross. The latter grinding station can be used by one operator to grind straight knife blades while the first mentioned station is being used to sharpen scissor type blades.

Accordingly, it is the object of the present invention tion to provide an improved power driven portable blade sharpener.

Another object of the invention is the provision of a portable blade sharpener having blade sharpening stations disposed on the opposite sides of a single abrasive wheel and adapted to be used simultaneously by separate operators to sharpen separate blades.

Another object of the invention is the provision of a power driven blade sharpener having simple easily adjusted means for presenting the edge of a knife blade against a revolving grinding wheel as it is pulled lengthwise of the blade across the grinding surface.

Another object of the invention is the provision of a simple effective and improved scissor blade holder adapted to grind scissor type blades of widely varying characters and design with the cutting edge properly presented to the grinding wheel.

These and other more specific objects will appear upon reading the following specification and cla ms and 70 upon considermg 1n connection therewith the attached drawings to which they relate.

Referring now to the drawings in which a preferred embodiment of the invention is illustrated:

Figure 1 is a perspective view of the portable blade sharpener of the present invention;

Figure 2 is an enlarged fragmentary sectional view taken on line 22 of Figure 1;

Figure 3 is a similar fragentary sectional view taken on line 33 of Figure l;

Figure 4 is a transverse sectional view on enlarged scale taken on line 4-4 of Figure l; and

Figure 5 is a fragmentary enlarged sectional view taken on line 5-5 of Figure 1.

Referring to Figure 1 there is shown a portable selfcontained blade sharpener designated generally 10 having a flat base plate 11 perferably provided with resilient feet 12 at its four corners. Rigidly secured to one corner of plate 11 in any suitable manner is a motordriven abrasive wheel unit comprising an electric motor 13 having a shaft 14 having an abrasive wheel 16 clamped to its outer end as by clamping nut 15. A first sharpening station arranged for the sharpening of elongated blades such as the butcher knife type blade 17 includes a pair of identical brackets 20 secured to base 11 adjacent the opposite side faces of wheel 16 as by cap screws 21. The upper ends 22 of each bracket flare outwardly and are provided centrally thereof with smooth bores 23 and at their upper'ends with threaded bores.

24. Supported through bores 23 by means of adjusting cap screws 25 are identical and adjustable blade guide plates 26. As appears from Figure 5, cap screws 25 fit loosely through bores 23 to the end that guide numbers 26 can be tilted toward or away from the adjacent faces of abrasive wheel 16. Locking screws 27 are seated in threaded bores 24 with their inner ends hearing against the outer faces of plates 26 to the end that the lower edges 29 of plates 26 can be held firmly against the adjacent sides of brackets 20 upon the tightening of lock screws 27.

The bodily shiftable blade support employed in connection with the second blade sharpening station will be best understood by reference to Figures 1 to 4. This support, designated generally 35, includes an elongated inverted T-shaped member provided with a smooth surfaced head 36 secured to a flange 37 of its stem 38 which cooperates with the vertical leaf 39 of a long hinge. Secured to the other hinge leaf 40 is a long flat plate 41 having a downwardly struck tab 42 extending into a compression spring 43 supported at its lower end by an upstruck tab 44 in head 36 and acting to bias plate 41 counterclockwise about pivot pin 45 as viewed in Figures 1 and 4. Acting to limit this pivotable movement of plate 41 is a thumbscrew 48 inserted through an opening 49 in plate 41 and having its end bearing against a stop lug 50 projecting from stem member 38.

Supported on plate 41 are a pair of scissor blade clamping and adiusting devices designated generally 53 and 54, respectively, the details of the former being shown in Figure 2 and the details of the latter being shown in Figure 3.

Clamp 53 comprises a fixed jaw 55 having its rear end rigidly clamped to plate 41, as by screws 56 and spools 57. A thumb screw 58 is threadedly supported in a bore 59 of jaw 55 and cooperates with the forward edge of plate 41 in clamping the handle end of a scissors blade 60 firmly in place.

The adjustable blade positioning clamp 54 shown in Figure 3 comprises a disk-like movable clamping jaw having an angular shoulder 66 on its under rim for clamping engagement with the rear edge of scissors blade 60. Clamping disk 65 is eccentrically mounted on plate 41 by a screw 68 extending through a shouldered bore 70 in plate 41. Screw 68 can be locked in an i or adjusted position as by a lock nut 69. Bore 70 seats a compression spring 71 effective to urge disk 65 upwardly along screw 68. A wing nut 73 threaded onto screw 68 enables the operator to clamp disk 65 against the rear edge of blade 60 with the cutting edge 75 presented well beyond the forward edge of plate 41. Owing to the eccentric location of bore '70 through disk 65, it will be apparent that clamp 54 will accommodate scissor blades of widely varying widths to the end that the cutting edge of the blade can be presented at the proper distance from the forward edge of plate ii. In certain instances it is highly desirable that the cutting edge be close to the edge of plate 41 for greater rigidity, while in others it is feasible and desirable that the edge be well forward of plate 41.

it will be understood that the described portable unit is provided with a service cord for motor 13 and a suitable control switch, not shown, for starting and stopping the motor. Rigidly secured to a stationary part of the unit is a carrying handle here shown as comprising a bracket 8t? having a hand grip S1 overlaying motor 3 at a point close to the center of gravity of the unit.

The mode of operation of the described unit will be quite apparent from the foregoing description of its several components. In sharpening a long knife blade, as 1'7, it may be necessary to adjust the supporting blades 26 at the upper end of brackets 20 in order that the cutting edge of the knife will be properly presented against the face of grinding wheel 60. This adjustment is easily accomplished by loosening lock screw 57 and adjusting screw 25 to support plate 26 at the proper angle after which lock screw 27 is firmly tightened to clamp it in this postion. The knife is then sharpened against the rotating wheel as the operator draws the blade forwardly across the face of the wheel while supported in the position shown in Figures 1 and 5, it

being understood that the knife blade is drawn alternately through the slot provided for on the opposite faces of the grinding wheel as very slight pressure is app-lied to the back edge of the blade.

The scissor blade grinding station can be used simultaneously by a separate operator using the scissor supporting device 35. "The scissors are opened wide and one blade is clamped beneath clamps 53 and 54. Usually the rear end of the blade is first clamped in clamp 53 after which clamp 54 is used to clamp the other end of the blade. After disk 65 has been rotated to present the blade edge at the proper distance forwardly of plate 41, thumbscrew 73 is tightened to lock the blade in place. Thumbscrew 48 is then adjusted to the extent necessary to tilt the blade about hinge axis 45 for the purpose of presenting cutting edge 75 at the proper angle to the rim edge of abrasive wheel 16.

The operator then grasps the opposite ends of device 35 between his hands and shifts it along the smooth upper surface of base plate 11 guiding it as necessary to apply edge 75 of the scissor blade lightly against the edge of the abrasive wheel, the device being moved at a uniform rate until the full length of the blade has been ground. One or more additional passes may be made to apply a finish grind although a single light-pressure pass usually suflices to sharpen the blade. Thereafter, the other blade of the scissors is clamped in. position following the same steps described above in order that it may be sharpened in like manner.

While the particular portable multiple-station blade sharpener herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is tobe understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A multiple-station power-driven blade sharpener 4 1 comprising a smooth surfaced base supporting on the upper surface thereof a motor driven abrasive wheel, means providing a plurality of blade grinding stations adapted to be separately manned simultaneously and located adjacent the diametrically opposed rim edges of said Wheel, a pair of blade supporting members he side the opposite side faces of said wheel at one operating station, a second operating station on the diametrically opposite side of said wheel and utilizing the rim edge thereof for sharpening, and bodily shiftable scissor blade holding mews slidable on the smooth surface of said motor-supporting base and adapted to support the edge of a scissors blade slightly inclined from a plane normal to the transverse edge of said wheel for sliding movement across said wheel edge, whereby two different operators positioned at said first and second stations respectively may use the same wheel simultaneously to sharpen separate blades without interference with one another.

2. A blade sharpener as defined in claim 1 characterized in that said pair of blade supporting members include similar knife blade supports each of which is provided with independent means for adjusting the angular position thereof relative to the adjacent side of said abrasive wheel.

3. A blade sharpener as defined in claim 1 characterized in that each of said pair of blade supporting members includes a support fixed to said base and having an upper end inclined outwardly way from the adjacent face of the abrasive wheel, a knife blade supporting plate movably supported on the inner side of said inclined ends of said fixed supports including one screw extending loosely through said inclined end and a second screw supported in said inclined end and bearing r against the side of said movable plate, said screws cooperating to lock said movable plate in a desired inclined knife blade supporting position relative to the face of said abrasive wheel.

4. A power driven blade sharpener comprising a flat base having a motor driven abrasive wheel secured to the upper surface thereof, an inverted T-shaped scissors support having a smooth surfaced flat head adapted to rest flush against and slide freely over said fiat base, a scissor blade clamping means hingedly connected to the upper end of the stem of said T-shaped support with the cutting edge of the scissor blade exposed in a generally horizontal position for sharpening by movement crosswise of abrasive wheel, spring means biasing said scissors clamp and a scissor blade clamped therein bodily in one direction about the axis of said hinge, and adjustable stop means for limiting the movement of said clamp by said biasing means.

5. A blade sharpener as defined in claim 4 characterized in that said scissor blade clamping means includes a pair of independent clamps spaced longitudinally of said T-shaped support.

6. A blade sharpener as defined in claim 5 characterized in that one of said blade clamping means includes an eccentrically supported disk having a flanged rim engageable over the rear .edge of a scissor blade and including a clamping screw for clamping said disk against a blade after the disk has been rotated to a desired position relative to its eccentric mounting.

7. A readily portable power-driven multiple-station blade sharpener assembly adapted to be manned simultaneously by separate operators performing separate grinding operations on different blades comprising, a base supporting a motor-driven abrasive wheel unit, said abrasive wheel having flat side faces and a cylindrical rim, a carrying handle for said unit assembly having a hand grip overlying said motor, said motor being offset laterally from the longitudinal center of said base to provide a smooth fiat rest for a bodily-movable scissor bladesupporting stand, a scissor blade support and clampingv stand slidably supported on said flat portion of the base and adapted to support a scissor blade for movement across the rim edge of the abrasive wheel, at one of said operating stations, and a second blade sharpening station disposed on the opposite side of said base and of said abrasive wheel and including means for supporting either side of a knife blade edge against the opposite faces of said wheel at the proper angle for sharpening.

8. An article of manufacture for use with a powerdriven abrasive wheel comprising a blade holder having an elongated support of inverted T-shape in cross section, the base of said support being flat and smooth for sliding support on a base plate, a long flat plate hinged to the upper end edge of said support and spring pressed downwardly toward the head of said T, an adjustable stop for limiting the hinging of said plate, and a pair of blade clamps carried by said plate along the free edge thereof and adapted to clamp a scissors blade and the like in position to be sharpened as said support is slid lengthwise with the blade edge passing crosswise and in contact with said edge of a driven abrasive wheel.

References Cited in the file of this patent UNITED STATES PATENTS 809,254 Golden Jan. 2, 1906 1,726,571 Kelley Sept. 3, 1929 2,191,600 Wahl Feb. 27, 1940 2,192,981 McMillen Mar. 12, 1940 2,565,291 Amendola Aug. 21, 1951 

